import numpy as np
import cv2 

cap = cv2.VideoCapture('/home/ishank/Desktop/Regular/17.avi')

fps = int(cap.get(cv2.CAP_PROP_FPS))
print(fps)
# params for ShiTomasi corner detection
feature_params = dict( maxCorners = 100,
                       qualityLevel = 0.3,
                       minDistance = 7,
                       blockSize = 7 )

# Parameters for lucas kanade optical flow
lk_params = dict( winSize  = (15,15),
                  maxLevel = 2,
                  criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03))

# Create some random colors
color = np.random.randint(0,255,(100,3))

# Take first frame and find corners in it
ret, old_frame = cap.read()
old_gray = cv2.cvtColor(old_frame, cv2.COLOR_BGR2GRAY)
p0 = cv2.goodFeaturesToTrack(old_gray, mask = None, **feature_params)

# Create a mask image for drawing purposes
mask = np.zeros_like(old_frame)
# Define the codec for output video
fourcc = cv2.VideoWriter_fourcc(*'MPEG')
# Set up output video stream
out = cv2.VideoWriter("tracking.avi", fourcc, fps, (old_gray.shape[1], old_gray.shape[0]))
# Reset stream to first frame
cap.set(cv2.CAP_PROP_POS_FRAMES, 0)
while(1):
    # Read next frame
    success, frame = cap.read()
    if not success:
        break
    frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    # calculate optical flow
    p1, st, err = cv2.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None, **lk_params)

    # Select good points
    good_new = p1[st==1]
    good_old = p0[st==1]

    # draw the tracks
    for i,(new,old) in enumerate(zip(good_new,good_old)):
        if i > 0:
            break
        a,b = new.ravel()
        c,d = old.ravel()
        mask = cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2)
        frame = cv2.circle(frame,(a,b),5,color[i].tolist(),-1)
    img = cv2.add(frame,mask)

    # cv2.imshow('frame',img)
    # k = cv2.waitKey(30) & 0xff
    # if k == 27:
    #     break
    # Write to output file
    # Define the codec for output video
    out.write(img)
    # Now update the previous frame and previous points
    old_gray = frame_gray.copy()
    p0 = good_new.reshape(-1,1,2)

cv2.destroyAllWindows()
cap.release()
